Double–Double: New Family of Composite Laminates

A new family of composite laminates could revolutionize composite structures to be lighter, stronger, easier to understand and design, and faster and lower cost to manufacture. For the last 60 years, traditional quad laminates (quad) based on collections of 0, ±45, 90 plies have controlled composite laminates. However, restriction to four specific angle orientations has unnecessarily limited design and production. The newly discovered laminate family, called double–double laminates (DD), based on two pairs of angle-plies, can redirect the trend instead toward simplicity and rationality. Advantages enabled by DD include homogenization, tapering to save weight, ply drop placement to improve quality, and card sliding to simplify ply stacking. A switch from quad to DD laminates can bring a renaissance to the composites industry for the production of better airplanes, cars, and other important engineering applications.